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<p>Hi William,</p>
<p>I looked at the data you sent me. The problem is likely
overexposed and that basically means very white value have band 1
to 3 set at 255,255,255. I tried three solutions.</p>
<p> The first is to make all the white pixels null pixel. Then
adding a Google Satellite layer under. The nodata pixels are
transparent. That solution does not work basically because of
pixel misregistration between both layers. It looks bad. See
2layer_solution in the project I sent you.</p>
<p>The second option is to interpolate the nodata values (the white)
using t.fill.stats found in the Processing toolbox, and then
recombining the bands (look at the Interpolated_band123 layer)
That could work but generally, pixel tend to become much darker.
This should not be the case because we are dealing with
highlights. Also, you have some highlights that are not
255,255,255 but very close. They now stick out. Maybe a better
interpolation can be found. I did not play with this much.<br>
</p>
<p>The best solution is the simplest. Use the green local stretch
icon in the raster toolbar (you may need to activate it). Under
layer > layer properties > Symbology set render type to
multiband color. Red: min = 32, max =207, Green: min = 26, max =
179, and Blue: Min = 33, max 152 give good results. But basically
zoom in and click the icon.</p>
<p>This way, you will not notice the overexposure and the colors
will be nicer. <br>
</p>
<p>Cheers!</p>
<p>Nicolas<br>
</p>
<p><br>
</p>
<div class="moz-cite-prefix">On 2020-05-24 12:01 a.m., William
Reynolds wrote:<br>
</div>
<blockquote type="cite"
cite="mid:CADk26xAc=QATuMn8-A-o7Z+NqcPyZNitMe3Qa6jVBFrjT5ky2g@mail.gmail.com">
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<div dir="ltr">I have a raster image I would like to assign a
value to the 3 RGB bands that are equal to 255. I have several
hundred raster images where the image is overexposed (white) and
band1=255, band2=255 and band3=255.
<div><br>
</div>
<div>Is there a way to run a script that would assign a new
value to each of the three bands if the band1, band2 and band3
values = 255?</div>
<div><br>
</div>
<div>Bill</div>
</div>
<br>
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